CO 2 hydrogenation for the acquisition of value-added chemicals is an economical means to deal with the CO 2 -relevant environmental problems, among which CO 2 reduction to CH 4 is an excellent model reaction for investigating the initial steps of CO 2 hydrogenation. For the supported catalysts commonly used in such reactions, the tailoring of the interfacial effect between metal centers and supporting materials so as to obtain superior low-temperature CO 2 methanation performance is a significant but challenging subject. In this work, we altered the size regimes of the Ru deposits in Ru/CeO 2 assemblies and uncovered the competitive relationship between the strong metal−support interactions (SMSI) and the H-spillover effect in determining the methanation activities by some ex situ and in situ spectroscopic techniques coupled with density functional theory (DFT) calculations. For CeO 2 nanowire supported single Ru atoms, Ru nanoclusters (ca. 1.2 nm in size), and large Ru nanoparticles (ca. 4.0 nm in size), the nanoclusters show the most outstanding low-temperature CO 2 methanation activity and 98−100% selectivity, with a turnover frequency (TOF) of 7.41 × 10 −3 s −1 at 190 °C. The negative CO 2 reaction order decreases their absolute values from single atoms to nanoclusters and turns positive in nanoparticles, while the positive H 2 reaction order follows the reverse tendency. In situ DRIFTS measurements demonstrate that the dominant reaction pathway is the CO route, in which metal carbonyls are the critical intermediates and the active sites are those Ce 3+ −OH sites and Ru sites near the metal−support interfaces in charge of CO 2 dissociation and carbonyl hydrogenation, respectively. Meanwhile, the strongest SMSI and H-spillover effect are respectively encountered in supported single Ru atoms and large Ru nanoparticles, with the activation of metal carbonyls and the dehydration of the support surfaces suppressed correspondingly. The two factors reach a balance in CeO 2 -supported Ru nanoclusters, and the methanation activity is therefore maximized. A mechanistic understanding of the interfacial effect in tuning the CO 2 methanation activities would shed light on the ingenious design of the CO 2 hydrogenation catalysts to utilize the SMSI and H-spillover effect to an appropriate degree and avoid their possible suppressions that would take place in extreme cases.

CdS/In2O3 hierarchical nanotubes with intimate and extensive contact between CdS and In2O3 were synthesized from a MOF and showed huge improvement of visible-light photocatalytic hydrogen production.

Bimetal‐S‐O composites have been rarely researched in electrochemical reduction of CO2. Now, an amorphous Ag‐Bi‐S‐O decorated Bi0 catalyst derived from Ag0.95BiS0.75O3.1 nanorods by electrochemical pre‐treatment was used for catalyzing eCO2RR, which exhibited a formate FE of 94.3 % with a formate partial current density of 12.52 mA cm−2 at an overpotential of only 450 mV. This superior performance was attributed to the attached amorphous Ag‐Bi‐S‐O substance. S could be retained in the amorphous region after electrochemical pre‐treatment only in samples derived from metal‐S‐O composites, and it would greatly enhance the formate selectivity by accelerating the dissociation of H2O. The existence of Ag would increase the current density, resulting in a higher local pH, which made the role of S in activating H2O more significantly and suppressed H2 evolution more effectively, thus endowing the catalyst with a higher formate FE at low overpotentials.

Abstract. The present study aims to prepare carvedilol (CAR) nanosuspensions using the anti-solvent precipitation-ultrasonication technique to improve its dissolution rate and oral bioavailability. Alphatocopherol succinate (VES) was first used as a co-stabilizer to enhance the stability of the nanosuspensions. The effects of the process parameters on particle size of the nanosuspensions were investigated. The optimal values of the precipitation temperature, power inputs, and the time length of ultrasonication were selected as 10°C, 400 W, and 15 min, respectively. Response surface methodology based on central composite design was utilized to evaluate the formulation factors that affect the size of nanosuspensions, i.e., the concentration of CAR and VES in the organic solution, and the level of sodium dodecyl sulfate in the antisolvent phase, respectively. The optimized formulation showed a mean size of 212±12 nm and a zeta potential of −42±3 mV. Scanning electron microscopy revealed that the nanosuspensions were flaky-shaped. Powder Xray diffraction and differential scanning calorimetry analysis confirmed that the nanoparticles were in the amorphous state. Fourier transform infrared analysis demonstrated that the reaction between CAR and VES is probably due to hydrogen bonding. The nanosuspension was physically stable at 25°C for 1 week, which allows it to be further processing such as drying. The dissolution rate of the nanosuspensions was markedly enhanced by reducing the size. The in vivo test demonstrated that the C max and AUC 0-36 values of nanosuspensions were approximately 3.3-and 2.9-fold greater than that of the commercial tablets, respectively.

No abstract

Co3O4 hierarchical nanosheets were synthesized by a self-templated strategy and showed excellent performance towards visible-light photocatalytic CO2 reduction to CO.

No abstract

No abstract